k-Factorization and impact factors at next-to-leading level Original Research Article

We further analyse, at next-to-leading log s level, the form of k-factorization and the definition of impact factors previously proposed by one of us, and we generalize them to the case of hard colourless probes. We then calculate the finite one-loop corrections to quark and gluon impact factors and we find them universal, and given by the same K factor which occurs in the soft timelike splitting functions.